Performance Details

As we all try to navigate through the economic mud that is our current international fiscal situations, pay the fare of bills due and find enough extra capitol to race with, it becomes ever more important to find in-expensive performance improvement areas. One such place to look is in the details of everything fast.

Successful, and top line professional racers “sweat the details.” Most racers, amateurs and those who wish to be professionals see only the “wonderful toys” of the professionals and never grasp the huge amount of work necessary to turn the same parts and equipment you and I can buy, into that extra tenth or so of a second on the race track.

For example, how many of us will take an engine apart, blue all of the gears, turn them to properly mark them and then carefully, one at a time, hand grind and fit each gear to its mate? Afterwards, you can feel the difference, in a gearbox, with your hand. The ease with which the “massaged” gear set can now be turned over is significant when compared to most stock units.

Work of this nature reduces frictional losses within the power train assembly of the vehicle. It takes power to make power. The more efficient your power train the less parasitic losses you must overcome to produce usable power. Efficiency improvements cost little more than time and effort.

We reached out to Bert Baker, the prick bastard of Baker driveline for a comment on the above process: When gear teeth are hobbed or shaper-cut before heat treat they are close to perfect as it relates to the involute tooth form, tooth-to- tooth spacing error, and lead. Heat treating the gear, a necessary evil for durability, turns the tooth into a potato chip as measured in the world of tenths of thousandths (.0001).

Blue-ing gear teeth and hand grinding/honing high spots off the gear tooth flanks to make them roll together smoother is a task only recommend for the highly experienced. The opportunities to make a mess far outweigh the potential improvements. In other words, it is a real bitch to hand grind a .0001-.0003 high bump off a tooth flank. Most people have no concept of how small that size ‘bump’ is. Therefore, do not try this at home, unless you know one of those old timers who has done it a 100 times. You know, that old pre-CNC cat who can take the verniers on a Bridgeport and make a perfectly round 6 inch circle in a piece of flat stock.

Special note: BAKER transmissions feature gears that are ground (corrected after heat treat) with a diamond coated tool on a state of the art, 1.5 million dollar machine. No tooth profle correction is required.

Many areas of drive trains and overall vehicle components, in general, are in-expensive to improve, but are often overlooked simply because they are not “big” power generators. Small improvements in details can and do mean the difference between not qualifying and racing on Sunday.

Everything is connected and symbiotic, and everything can and often does effect everything else in some way or form.

The exhaust system is an area that is all too often overlooked and one where details can and do make a major positive difference. The majority of stock and aftermarket exhaust systems are not perfectly finished inside. We base our purchases upon marketing and advertising, feedback from other racers and external looks. But the gasses and finite waves that move through the inside of your exhaust system do not care about marketing, pit gossip or what the outside of your exhaust system looks like. What they do care about is weld splatter, and glob build up, sharp un-finished edges, ragged collector junctions, abrupt changes in size and radius curves and angles. Most exhaust systems have some or all of these problems inside of them to a lesser or a greater degree.

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This is the picture of the inside of a four-into-one exhaust system I received from a local San Diego, California area shop. As you can see the insides of the pipes and collector are heavily laden with weld globs and collector mismatched components. There are finite compression and expansion waves moving through an intake and exhaust system. These waves carry the gasses out of the pipe and also return back to the cylinder and can assist in the movement of intake gasses during camshaft overlap.

The speed with which the gasses move and evacuate the cylinder, and the intensity of these wave formations during overlap can and do assist in power increases. Gas speed and intensity of the return wave during overlap, is directly related to the exhaust gas temperature and the ability to maintain that temperature consistently throughout the length of your exhaust system. This is where exhaust wraps and more effectively thermal coating can and are of additional assistance. But no matter how effectively coated and temperature consistent your exhaust system is, you cannot make the most efficient use of it, if the inside is filled with weld globs, the pipes are miss- matched and bends are sharp or abrupt.

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Air and gases do not see the inside of a pipe the same way that we do visually. A pipe that has even a small weld or mismatched area can, and does create an area of turbulence that will reduce the gasses ability to smoothly transition through a particular exhaust chamber. Sharp edges and changes in diameter inside the pipe will play havoc with the finite waves and tuning. A 1-inch pipe could, with turbulent areas, be reduced to a ¾- inch or even smaller pipe as the exhaust gasses see it. In short, you are choking off your engine’s ability to exhale and breathe, and it results in difficult tuning and poor performance.

So what to do? You can start by cleaning the header, inside and out. Then gently grind down all the weld splatter, which can easily and rationally be reached. You can also gently radius all of the sharp edges transitioning from one part of the pipe to another, and or mating surfaces and joints. A note of caution here, BE CAREFUL!!! Older pipes especially rusty ones can be quite thin, as to pipe wall thickness. If you grind away too much, you may grind through or make the pipe very thin. Again, BE CAREFUL!!!

The merge collector is another area that can usually use additional attention. If you have the ability to shape the merging sections into a point or smooth radius do so. But first, be aware of how the pipes were welded and assembled, and what the outside of the pipe is like. Do all of your merging pipes actually touch or are there gaps which when ground inside will create holes outside.
LOOK AND EVALUATE BEFORE YOU GRIND!!!

If you cannot grind the pipe then find someone who can. It’s also good to know a welder.

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If your collector section is truly a mess you might want to consider Burns Stainless for one of their beautiful merge collectors. This is not the specific aim of this article but sometimes parts and pieces are beyond an easy fix. If it will take more time and money to fix a sub-standard part, then the least expensive thing to do is to purchase quality parts and services in the first place. Again, evaluate and buy smart.

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A good pipe will be improved with thermal coating and or wrap. Keeping the heat inside the header unit as explained earlier is a good thing. When the pipe’s temperature is more uniform so too is the engines reaction to atmospheric and jetting changes, one less, or at least a smaller variable. When all of the other work is done then finish the pipe work off with Thermal coating, it is in-expensive insurance.

All of this will garner you consistent, usable power. This covered just a couple of performance details. There’s more, hang on.